#include <bits/stdc++.h>
using namespace std;

class Test{
public:
	int fourSumCount(vector<int>& A, vector<int>& B, vector<int>& C, vector<int>& D){
		int count = 0;
		unordered_map<int,int> m;
		for(int i : A){
			for(int j : B){
				m[i+j]++;
			}
		}
		for(int i : C){
			for(int j : D){
				int target = 0 - (i+j);
				if(m.find(target) != m.end()){
					count+=m[target];
				}
			}
		}
		return count;
	}
};


int main(){
	
	
	return 0;
}
